1. Field of the Invention
The present invention relates to a display device.
2. Description of the Related Art
In recent years, an image display device (hereinafter referred to as “organic EL (electro-luminescent) display device”) using self-emitting bodies called “organic light emitting diodes (OLED)” has been put into a practical use. As compared with a liquid crystal display device in a related art, the organic EL display device uses the self-emitting bodies, and therefore not only is excellent in visibility and response speed, but also does not require an auxiliary lighting device such as backlight. As a result, the organic EL display device can be further thinned.
Because an organic EL element used in the organic EL display device of this type is deteriorated when absorbing moisture, measures are taken to hermetically bond a sealing glass substrate onto a TFT (thin film transistor) substrate on which a light emitting layer is formed with resin in an organic EL panel.
JP 2005-148335 A discloses that in an evaporation mask in which plural openings for forming an organic light emitting layer are formed, since a shape of openings formed outside is changed by a stress, an opening as a dummy pixel is formed in a non-display area around a display area in the evaporation mask. JP 2007-256968 A discloses that a dummy pixel area is provided outside of the display area in a manufacturing stage for the purpose of equalizing film forming conditions for pixels in the display area.